How to Disable system write protection.!!!

I have a problem with my device htc e8 dual.
I use http://ift.tt/2axgTAi but it not work.
While i type in Terminal emulator, it not found.
Help me please.
My phone is htc e8 dual 5.0.2, kernel 3.4.0.
If you have a rom or kernel can fix it, please show me!

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